12,232 research outputs found
Newton slopes for Artin-Schreier-Witt towers
We fix a monic polynomial over a finite field and
consider the Artin-Schreier-Witt tower defined by ; this is a tower of
curves , with total
Galois group . We study the Newton slopes of zeta functions of
this tower of curves. This reduces to the study of the Newton slopes of
L-functions associated to characters of the Galois group of this tower. We
prove that, when the conductor of the character is large enough, the Newton
slopes of the L-function form arithmetic progressions which are independent of
the conductor of the character. As a corollary, we obtain a result on the
behavior of the slopes of the eigencurve associated to the Artin-Schreier-Witt
tower, analogous to the result of Buzzard and Kilford.Comment: 15 pages, upon the refereed version (to appear in Math. Ann), we
fixed two minor errors, one in the proof of Theorem 3.8, the other for
Theorem 4.
Slopes for higher rank Artin-Schreier-Witt Towers
We fix a monic polynomial over a finite field
of characteristic , and consider the
-Artin-Schreier-Witt tower defined by ; this
is a tower of curves , whose Galois group is canonically isomorphic to
, the degree unramified extension of
, which is abstractly isomorphic to as a
topological group. We study the Newton slopes of zeta functions of this tower
of curves. This reduces to the study of the Newton slopes of L-functions
associated to characters of the Galois group of this tower. We prove that, when
the conductor of the character is large enough, the Newton slopes of the
L-function asymptotically form a finite union of arithmetic progressions. As a
corollary, we prove the spectral halo property of the spectral variety
associated to the -Artin-Schreier-Witt tower. This
extends the main result in [DWX] from rank one case to the higher rank
case .Comment: 20 page
Robust Half-Metallic Character and Large Oxygen Magnetism in a Perovskite Cuprate
The new perovskite cuprate material SrCaReCuO, which
behaves ferrimagnetically and shows an unusually high Curie temperature ( 440 K), is found from density-functional theory calculation to display
several surprising properties after hole doping or chemical substitution: (1)
Half metal (HM) is realized by replacing Re with W or Mo while remains
high; (2) hole-doped SrCaReCuO is also HM with high
. Moreover, we find that the O atoms will carry a large magnetic moment
after hole doping, which is in sharp contrast with the generally accepted
concept that magnetism in solid requires partially filled shells of or
electrons in cations. The material SrCaReCuO is therefore
expected to provide a very useful platform for material design and development.Comment: 5 pages and 4 figure
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